View Full Version : Summary of Responses on Impact Loads in Rearfoot Striking onRunning Injuries

03-19-2010, 03:29 PM

Thank you all for the excellent responses to my question of whether the impact peak that is seen specific to rearfoot striking running is likely to produce running injuries. I have recently become more interested in this topic due to my involvement in debating the potential merits of barefoot versus shod running in the popular press. In addition, in my private sports podiatry practice, many of my runner-patients are curious about the barefoot running fad and its potential health/performance implications.

My personal impression, both from my sports medicine practice and from my 40 years as a distance runner, is that rearfoot striking and midfoot/forefoot striking running styles are self-selected styles of running, neither of which is better or with less injury-risk than the other. One thing that I have noted in the clinical examination of runners over the past 25 years is that the vast majority of runners that tend to naturally choose to be midfoot/forefoot strikers (versus choosing to be a rearfoot striker) while running shod have restrictions in passive ankle joint dorsiflexion with the knee flexed (i.e. soleus/ankle equinus) when compared to the rearfoot striking runners. Possibly those runners, while running shod, that have adequate ankle joint dorsiflexion with the knee flexed will naturally choose to rearfoot strike and those that have inadequate ankle joint dorsiflexion with the knee flexed will naturally choose to midfoot/forefoot strike at slower running speeds? This idea is something certainly to chew on for all of you who are looking for potential research projects on this fascinating subject.

Thanks again for all the excellent responses that follow.



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Kevin A. Kirby, DPM
Clinical Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt University
Private Practice:
107 Scripps Drive, Suite 200
Sacramento, CA 95825 USA

Voice: (916) 925-8111 (916) 925-8111 Fax: (916) 925-8136
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Dear Dr. Kirby,

This paper was published in nature and perhaps can help you.

Lieberman DE, Vankadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, Mang’Eni RO, Pitsiladis Y: Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature 463: 531-536, 2010.



Koosha Aslani M.S.
Research Engineer, Bioengineering Laboratory
Department of Orthopaedics
The Warren Alpert Medical School of Brown University / Rhode Island Hospital
email: kaslani@lifespan.org
phone: 401-444-4567 401-444-4567
fax: 401-444-4418
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We met at CSUS while I was in the PT program, and while I was doing research with Rafael Escamilla. Hope you're well.

I'm at University of Delaware now, and research is being conducted on your very question. Attached is an abstract.

Altman AR, Davis IS: Is midfoot striking during running advantageous over rearfoot or forefoot striking?

Toran MacLeod

Toran MacLeod PT, MS
PhD Student, BIOMS program

University of Delaware
Mechanical Engineering
126 Spencer Lab
130 Academy St
Newark, DE 19716

m. 707.318.2662
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Great question and very timely, after Lieberman's recent paper in

I am not aware of any studies that found an association between impact
peak or high loading rate and running injuries.

About 15 years ago I did a thorough review of literature on relationship
between impact load and OA. There have been many attempts to show a
relationship, but there seems to be no epidemiological evidence
whatsoever that people who do a lot of running have an earlier onset of
OA. Of course those are not randomized trials, there is a selection
bias because people tend to stop running when they have pain. But if
there was any relationship, I think it would have been shown in
epidemiological studies.

My explanation is that the external ground reaction force is only a
minor component of the internal loads on joints and bones. Internal
forces are several times higher, and mainly generated by muscles.
Muscles are soft tissue and don't generate or transmit such impact
peaks. So the bones and joints will hardly notice the impacts.

The comparative view is also interesting. Metal horseshoes produce huge
impact forces but no injuries.

Ton van den Bogert
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Hi Kevin,

Here are two you may find interesting, or helpful.


Rob Kell

Dr. Robert Kell
Assistant Professor, Work Physiology
Dept. of Social Sciences
University of Alberta
Augustana Campus
4901 - 46 Avenue
Camrose, AB T4V 2R3

Phone: (780) 679-1651
Fax: (780) 679-1590
email: rob.kell@ualberta.ca

Boyer, K. A. and T. P. Andriacchi (2009). "Changes in running kinematics and kinetics in response to a rockered shoe intervention." Clin Biomech (Bristol, Avon) 24(10): 872-6.
BACKGROUND: A suggested link between ambulatory mechanics and injury development has resulted in significant interest the development of footwear to change locomotion patterns. The purpose of this study was to test the hypothesis that there will be significant changes in the kinematics and kinetics at the ankle and minimal changes at the knee and hip in the mechanics of running in a shoe with a sagittal plane curvature relative to a flat soled shoe. METHODS: During running 3-D lower extremity kinematics and kinetics for 19 healthy volunteers were quantified using an optoelectronics system and a force plate. Data were collected for a flat sole conventional shoe (New Balance 658 (Control)) and a shoe with a rounded sole in the sagittal plane (Masai Barefoot Technologies (MBT)). Data were compared for the two shoe conditions using paired Student t-tests (alpha=0.05). FINDINGS: The ankle dorsi-flexion angles at heel-strike and mid-stance were greater, while the ankle plantar and dorsi-flexion moments and peak ankle joint power were significantly lower with the MBT relative to the control (P